Structure for preventing adhesion of microorganisms and method of manufacturing the same

ABSTRACT

The present invention relates to a structure for preventing the adhesion of microorganisms, which is capable of preventing microorganisms from adhering to and growing on a surface of an object, and a method of manufacturing the same. The structure for preventing the adhesion of microorganisms includes: a nano-structure configured to include a plurality of protruding structures each having a sharp end, and made of a resin composition; and a plurality of nano-metal particles configured to be distributed inside the nano-structure. A method of manufacturing a structure for preventing adhesion of microorganisms includes preparing a liquid resin; mixing the liquid resin with nano-metal particles; depositing the liquid resin on a substrate; pressing the liquid resin with a master template on which a pattern corresponding to a plurality of protruding structures is formed; and setting or curing the liquid resin.

BACKGROUND 1. Technical Field

The present invention relates generally to a structure for preventingthe adhesion of microorganisms and a method of manufacturing the same,and more specifically to a structure for preventing the adhesion ofmicroorganisms, which is capable of preventing microorganisms fromadhering to and growing on a surface of an object by means of a micro-or nano-pattern and nano-metal particles, and a method of manufacturingthe same.

2. Description of the Related Art

Generally, cases where microorganisms float and survive individually arefew. In most cases, microorganisms form three-dimensional (3D)structures by means of polymer materials produced by them. Such a 3Dstructure is called a biofilm. A biofilm formed by microorganisms may beformed on almost all types of solid surfaces or the tissues of livingcreatures.

FIG. 1 shows a process in which microorganisms adhere to a surface of asolid object and form a biofilm. When microorganisms floating in the airadhere to a surface of a solid object, the microorganisms secrete apolymer material, form a biofilm, and grow in the state in which thebiofilm has been formed. Furthermore, when the microorganisms continueto grow, the biofilm grows also. At some point, part of themicroorganisms is separated from the biofilm, and floats in the air.

In particular, in an infection process, pathogens may form biofilms onmedical instruments, such as catheters, various types of implants,artificial organs, etc., and may also form biofilms on all types ofartificial structures, such as water service pipes, sewer pipes, waterpurifiers, air purification facilities, etc, which are accessible tomicroorganisms. Accordingly, preventing a biofilm from being formed haslong been a concern for various technical fields, such as the civilengineering field, the architectural field, the urban engineering field,and the environmental engineering field, etc., as well as the medicalfield.

Therefore, in order to prevent microorganisms from growing, it isnecessary to prevent microorganisms from adhering to and forming abiofilm on a surface of a solid object. For this purpose, a technologyof forming a micro- or nano-pattern on a surface is known. FIG. 2 is asectional view showing a micro- or nano-pattern disclosed in EP 2 979844 published on Feb. 3, 2016. In this patent, a synthetic polymer film34A is formed on a base film 42A, and a plurality of raised portions34Ap is formed on the synthetic polymer film 34A. The raised portions34Ap of the above-described structure are formed in sharp protrudingshapes. The raised portions 34Ap destruct the cell walls ofmicroorganisms or bacteria, thereby preventing microorganisms fromadhering to and growing on a surface of the structure.

A technology of coating a surface of a solid object with nano-particlesof a metal, such as copper or silver, is known as another microorganismgrowth prevention technology. It is known that when nano-particles ofcopper or silver penetrate into microorganisms, the microbial metabolismof the microorganisms is disrupted and thus a sterilization effect isachieved. Generally, a deposition technology, such as sputtering or ionplating, is chiefly used to form or apply such nano-metal particles on asurface of a solid object.

Although various technologies for preventing microorganisms fromadhering to and growing on a surface are known, as described above, theuse of only the nano-metal particle coating or micro-structures havingtips has limitations on achieving sufficient sterilization capability.

Furthermore, according to Japanese Unexamined Patent ApplicationPublication No. 2009-174031, in order to coat a surface of an objectwith nano-metal particles, a sputtering process is used, or a technologyof generating a nano-metal particle colloid by reacting a porous carrierwith a metal precursor and fixing metal nano-particles onto a surface ofa processing target object in the metal nano-particles colloid is used.However, these conventional nano-metal particle coating technologiesrequire a high cost or a complex process, which is a cause of anincrease in manufacturing cost.

SUMMARY

The present invention has been conceived to overcome the above-describedproblems of the prior art, and an object of the present invention is toprovide a structure for preventing the adhesion of microorganisms, whichcan provide a microorganism adhesion prevention effect considerablyimproved over the effect of the conventional structures for preventingthe adhesion of microorganisms, and to also provide a method ofmanufacturing the structure for preventing the adhesion ofmicroorganisms, which can economically and conveniently manufacture thestructure for preventing the adhesion of microorganisms.

According to an aspect of the present invention, there is provided astructure for preventing the adhesion of microorganisms, which iscapable of preventing microorganisms from adhering to and growing on asurface of an object, the structure including: a nano-structureconfigured to include a plurality of protruding structures forpreventing the adhesion of microorganisms, and made of a resincomposition; and a plurality of nano-metal particles configured to bedistributed in the nano-structure; wherein the distribution of thenano-metal particles is controlled by means of an electric field so thatthe nano-metal particles are distributed in larger quantities in adirection toward a surface of the nano-structure.

The protruding structures may be a plurality of tip-shaped structureseach having a sharp end.

The protruding structures may be one of sinusoidal structures,column-shaped structures, and inverted U-shaped structures.

The plurality of nano-metal particles may be made of one or more metalsselected from the group consisting of copper Cu, silver Ag, platinum Pt,gold Au, zinc Zn, and palladium Pd.

The plurality of nano-metal particles may be distributed on the surfaceof the nano-structure.

The plurality of nano-metal particles may be distributed inside thenano-structure, and the density of the distribution of the nano-metalparticles may decrease in a direction inward from the surface of thenano-structure.

According to another aspect of the present invention, there is provideda method of manufacturing a structure for preventing adhesion ofmicroorganisms, which is capable of preventing microorganisms fromadhering to and growing on a surface of an object, the method including:preparing a liquid resin; mixing the liquid resin with nano-metalparticles; depositing the liquid resin on a substrate; pressing theliquid resin with a master template on which a pattern corresponding toa plurality of protruding structures is formed; controlling thedistribution of the nano-metal particles by applying an electric fieldto the master template; and setting or curing the liquid resin.

The method may further include, after setting or curing the liquidresin, performing a post process so that the nano-metal particles areexposed out of a surface of the set or cured resin.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more clearly understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a conceptual diagram showing a process in which microorganismsadhere to a surface of a structure and form a biofilm;

FIG. 2 shows a conventional structure for preventing the adhesion ofmicroorganisms;

FIG. 3 is a perspective view of a structure for preventing the adhesionof microorganisms according to a first embodiment of the presentinvention;

FIG. 4 is a side sectional view of the structure for preventing theadhesion of microorganisms according to the first embodiment of thepresent invention;

FIG. 5 is a side sectional view of a structure for preventing theadhesion of microorganisms according to a second embodiment of thepresent invention;

FIG. 6 is a flowchart showing a process of manufacturing a structure forpreventing the adhesion of microorganisms according to the presentinvention;

FIG. 7 shows a state in which nano-metal particles have been mixed witha liquid resin;

FIG. 8 shows a state in which the liquid resin has been deposited onto asubstrate;

FIG. 9 shows a state in which a pattern has been formed on the liquidresin by pressing the liquid resin deposited on the substrate with amaster template;

FIG. 10 shows a state in which the distribution of the metalnano-particles mixed with the liquid resin has been controlled byapplying an electric field to the master template;

FIG. 11 shows a state in which a solidified nano-structure has beenformed by setting or curing the liquid resin; and

FIG. 12 shows a state in which the metal nano-particles have beenexposed out of the nano-structure by eliminating a resin material from asurface of the solidified structure of FIG. 11.

DETAILED DESCRIPTION

FIG. 3 is a perspective view of a structure 100 for preventing theadhesion of microorganisms according to a first embodiment of thepresent invention. The structure for preventing the adhesion ofmicroorganisms includes a set of tip-shaped structures each having asharp end. The tip-shaped structures are generally fabricated in pyramidor cone shapes.

Although the structure for preventing the adhesion of microorganisms isconfigured to include the set of tip-shaped structures each having asharp end in order to maximize a sterilization effect in the embodimentshown in FIG. 3, the structure for preventing the adhesion ofmicroorganisms is not limited to the tip-shaped structures as long asprotruding structures capable of preventing microorganisms from adheringto a surface of an object are used. For example, a plurality ofsinusoidal structures, column-shaped structures, and inverted U-shapedstructures protruding from a plane can also prevent microorganisms fromadhering to a surface of an object.

Although the present invention will be described below with a focus ontip-shaped structures capable of providing a maximized effect, it willbe apparent to a person skilled in the art that the followingdescription can be also applied to protruding structures (sinusoidalstructures, column-shaped structures, inverted U-shaped structures,etc.), other than the tip-shaped structures.

FIG. 4 is a sectional view of the structure 100 for preventing theadhesion of microorganisms according to the first embodiment of thepresent invention. The structure 100 for preventing the adhesion ofmicroorganisms is formed on a substrate 200. The structure 100 forpreventing the adhesion of microorganisms includes: a nano-structure 130made of a polymer resin; and nano-metal particles 120 formed on asurface of the nano-structure 130. In this case, the substrate 200 maybe a surface of a device which requires that a structure for preventingthe adhesion of microorganisms is formed thereon.

Furthermore, the nano-structure 130 includes a plurality of tip-shapedstructures each having a sharp end. Although the tip-shaped structuresmay be generally pyramid-shaped structures or cone-shaped structures,they are not limited to a specific shape as long as they are shaped tohave sharp ends and can thus influence the cell membranes ofmicroorganism.

The nano-structure 130 is made of a resin composition for the sake ofease of manufacture. For example, the nano-structure 130 is made of anultraviolet curable resin composition which remains in a liquid phasebefore curing and is solidified when ultraviolet rays are radiatedthereonto. Although the ultraviolet curable resin composition includesacryl- or epoxy-based ultraviolet curable resin compositions, theultraviolet curable resin composition is not limited thereto as long asan ultraviolet curable resin composition which is in a liquid phasebefore curing and is transformed into a solid phase after curing isemployed. Moreover, the nano-structure 130 according to the presentinvention may be also made of a thermosetting resin composition, such asa phenol resin, an epoxy resin, or the like.

The dimensions of the tip-shaped structures constituting part of thenano-structure 130 may vary depending on a sterilization target.Generally, it was found that a desirable effect was achieved when thedistance (pitch; D) between the tips of the tip-shaped structures rangedfrom 200 to 300 nm and the vertical distance (height; H) from thebottoms of the tip-shaped structures to the tips thereof ranged from 300to 500 nm.

For reference, although the effect will increase as the height H of thetip-shaped structures increases, the height H of the tip-shapedstructures may be determined at a appropriate level (which is two ormore times the width of the tip-shapes structures) by taking intoaccount the limitations of technology for manufacturing anano-structure, manufacturing cost, etc. Furthermore, the pitch of thetip-shaped structures may be designed to be ½ to ⅓ of the size ofmicroorganisms (bacteria).

The nano-metal particles 120 are not limited to a specific type of metalas long as the metal of the nano-metal particles 120 is effective insterilization. It is generally known that nano-particles of copper Cu,silver Ag, platinum Pt, gold Au, zinc Zn, and palladium Pd havedesirable effects. The optimum size of the nano-metal particles 120 mayvary depending on a sterilization target.

According to the first embodiment of the present invention, whenmicroorganisms approach the structure 100 for preventing the adhesion ofmicroorganisms, the nano-metal particles 120 present on the surface ofthe structure 100 for preventing the adhesion of microorganismspenetrate into the microorganisms and then disrupt the microbialmetabolism of the microorganisms. In this case, when the tips of thenano-structure 130 destruct the cell membranes of the microorganisms, asterilization effect is amplified. Accordingly, this can achieve animproved effect compared to a case where only a nano-structure ornano-metal particles are present.

FIG. 5 is a sectional view of a structure 100 for preventing theadhesion of microorganisms according to a second embodiment of thepresent invention. The structure 100 for preventing the adhesion ofmicroorganisms according to the second embodiment of the presentinvention is different in the distribution of nano-metal particles 120from the structure 100 for preventing the adhesion of microorganismsaccording to the first embodiment of the present invention. Thenano-metal particles 120 are concentrated on the surface of thenano-structure 130 in the first embodiment, whereas nano-metal particles120 are additionally distributed inside a nano-structure 130 in thesecond embodiment.

Generally, it is advantageous in a cost-effectiveness aspect that allthe nano-metal particles 120 are concentrated on the surface of thenano-structure. Meanwhile, when the structure 100 for preventing theadhesion of microorganisms is used in an environment where it isdifficult to replace the structure 100, nano-metal particles present onthe surface of the nano-structure 130 may be lost due to abrasion or thelike attributable to long-term use. In contrast, when a structure forpreventing the adhesion of microorganisms, such as that according to thesecond embodiment, is utilized, metal nano-particles 120 present insidethe surface continue to perform a sterilization function in place of thelost nano-metal particles. In this case, although the metalnano-particles 120 may be uniformly distributed throughout the inside ofthe nano-structure 130, the density of the distribution of the metalnano-particles 120 may be highest on the surface of the nano-structure130, and may decrease in a direction inward from the surface of thenano-structure 130.

FIG. 6 is a flowchart showing a process of manufacturing a structure forpreventing the adhesion of microorganisms according to the presentinvention, and FIGS. 7 to 12 show the individual steps of the aboveprocess shown in the flowchart.

Referring to FIG. 7, step S100 of preparing a liquid resin and step S200of mixing the prepared liquid resin with nano-metal particles areperformed. Although the liquid resin may be an ultraviolet curableresin, a thermosetting resin may be used as the liquid resin. Althoughit may be helpful to a post process to uniformly distribute thenano-metal particles inside the liquid resin, the nano-metal particlesare re-distributed inside the liquid resin due to an electric field, andthus the uniformity of the nano-metal particles is of no particularimportance.

FIG. 8 shows step S300 of depositing the prepared liquid resin 300,mixed with the nano-metal particles at step S200, on a substrate 400. Inthis case, the substrate 400 is a manufacturing tool temporarily usedfor the process of manufacturing a structure for preventing the adhesionof microorganisms, and is distinct from the above-described substrate200.

FIG. 9 shows step 400 of placing a master template 500 on the liquidresin 300 deposited on the substrate 400 and pressing the liquid resin300 with the master template 500. A pattern having a shape correspondingto the shape of a nano-structure 130 including tip-shaped structures isformed on a surface of the master template 500, and a surface of theliquid resin 300 is formed in a shape corresponding to the shape of thepattern.

FIG. 10 shows step S500 of applying an electric field to the mastertemplate 500. When a positive electric field is applied as an example,the nano-metal particles 120 distributed inside the liquid resin 300 aremoved within the resin, i.e., a liquid, by the force of the electricfield, with the result that the nano-metal particles 120 are movedtoward a portion where the master template 500 and the liquid resin 300come into contact with each other. Therefore, the shape of thedistribution of the nano-metal particles 120 inside the liquid resin 300can be controlling by adjusting the strength of the electric field andthe time for which the electric field is applied.

FIG. 11 shows step S600 of thermally setting or optically curing theliquid resin. Through the setting or curing process, the resin havingflowability loses flowability and is solidified, and thus thenano-structure 120 is formed.

FIG. 12 shows step S700 of performing a post process on the patternedsurface of the set or cured resin. This step is performed to eliminate athin resin film covering the nano-metal particles 120 so that nano-metalparticles 120 present near the surface of the nano-structure 120 can beexposed out of the nano-structure 120. Although this step may beperformed through blasting, the step is not limited to a specific methodas long as a method for performing this step can eliminate the thinresin film.

The structure for preventing the adhesion of microorganisms manufacturedusing the above-described method may be used to prevent biofilms to beformed on medical instruments, such as catheters, various types ofimplants, artificial organs, etc., and may be applied to all types ofartificial structures, such as water service pipes, sewer pipes, waterpurifiers, air purification facilities, etc, which are accessible tomicroorganisms.

The structure for preventing the adhesion of microorganisms according tothe present invention is made of a polymer resin which is relativelyinexpensive and is easy to handle, has protruding shapes capable ofpreventing microorganisms from adhering to the surface of the structure,and includes distributed nano-metal particles, so that the adhesion ofmicroorganisms to the surface can be delayed and the nano-metalparticles can penetrate into the cells of the microorganisms, therebyproviding sterilization capability.

Furthermore, when the protruding nano-structures are a plurality oftip-shaped structures each having a sharp end, the cell membranes ofmicroorganisms are destructed by tips, and the nano-metal particles caneasily penetrate into the cells of the microorganism, thereby maximizingsterilization capability.

Moreover, according to the present invention, the nano-metal particlesare disposed using a method of distributing nano-metal particles towardthe surface of the structure by inducing the nano-metal particlesfloating inside the polymer resin before setting or curing to move in anelectrical manner, rather than a method such as sputtering or the like,and thus a manufacturing process is simplified and manufacturing costcan be significantly reduced.

Although the specific embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible without departing from the scope and spirit of the invention asdisclosed in the accompanying claims.

1. A structure for preventing adhesion of microorganisms, which iscapable of preventing microorganisms from adhering to and growing on asurface of an object, the structure comprising: a nano-structure layerincluding a plurality of patterned protrusions, wherein the patternedprotrusions form a top surface of the nano-structure layer and preventadhesion of microorganisms, and the nano-structure layer is made of aresin composition; and a plurality of nano-metal particles distributedin the nano-structure layer; wherein the distribution of the nano-metalparticles is controlled by means of an electric field so that density ofthe nano-metal particles is highest at the top surface of thenano-structure layer and decreases in a direction inward from the topsurface of the nano-structure layer.
 2. The structure of claim 1,wherein the patterned protrusions are a plurality of tip-shapedstructures each having a sharp end.
 3. The structure of claim 1, whereinthe patterned protrusions are one of sinusoidal structures,column-shaped structures, and inverted U-shaped structures.
 4. Thestructure of claim 1, wherein the plurality of nano-metal particles ismade of one or more metals selected from the group consisting of copperCu, silver Ag, platinum Pt, gold Au, zinc Zn, and palladium Pd.
 5. Astructure for preventing adhesion of microorganisms, which is capable ofpreventing microorganisms from adhering to and growing on a surface ofan object, the structure comprising: a nano-structure layer including aplurality of patterned protrusions, wherein the patterned protrusionsform a top surface of the nano-structure layer and prevent adhesion ofmicroorganisms, and the nano-structure layer is made of a resincomposition; and a plurality of nano-metal particles distributed in thenano-structure layer, wherein the plurality of nano-metal particles isdistributed on the top surface of the nano-structure layer. 6.(canceled)
 7. A method of manufacturing a structure for preventingadhesion of microorganisms, which is capable of preventingmicroorganisms from adhering to and growing on a surface of an object,the method comprising: preparing a liquid resin; mixing the liquid resinwith nano-metal particles; depositing the liquid resin on a substrate;pressing the liquid resin with a master template on which a patterncorresponding to a plurality of protruding structures is formed;controlling distribution of the nano-metal particles by applying anelectric field to the master template; and setting or curing the liquidresin.
 8. The method of claim 7, further comprising, after setting orcuring the liquid resin, performing a post process so that thenano-metal particles are exposed out of a surface of the set or curedresin.